Background technique
Known closed rankine cycle comprises: the ebullator or the vaporizer that are used for dynamafluidal evaporation; Has steam from the supply of this ebullator so that drive the turbo machine of generator or other load; Be used for making condenser from the discharge vapour condensation of this turbo machine; And be used to make that the fluid re-circulation of condensation arrives the device of this ebullator, for example pump.U. S. Patent 3393515 has disclosed this system.
This rankine cycle system is generally used for generating, and the electric power that sends can be supplied to electrical distribution system or electrical network, so that domestic civilian and commercial.Employed motive fluid water normally in this system, wherein turbo machine is driven by steam.The thermal source that is supplied to ebullator can be any type of fossil fuel, for example oil, rock gas or nuclear energy.Turbine design becomes to be convenient to work under higher pressure and temperature in this system, and its manufacturing cost and use cost is higher.
When energy crisis occurring; and when needing energy saving and need use the available energy efficiently, can use rankine cycle system to collect " used heat ", otherwise these used heat will be discharged in the atmosphere; because generating needs more fuel, so this will destroy environment indirectly.
In garbage loading embeading is used, can obtain a kind of thermal source of routine, wherein exhale the methane gas that causes Global Greenhouse Effect.In order to prevent that methane gas from entering in the environment and the aggravation Global Greenhouse Effect, proposed to make this gaseous combustion by so-called " flaring ".Although the product (CO of methyl hydride combustion
2And H
2O) do not destroy environment, but wasted utilizable a large amount of energy.
The another kind of mode of using methane gas effectively is a combustion of methane gas in diesel engine or less combustion gas turbine or Microturbine, so that drive generator, electric power directly is supplied to the equipment of electrification or turns back to electrical network subsequently.When using diesel engine or Microturbine, must at first wait and purify methane gas by filter; And if used diesel engine, this also must relate to a large amount of maintenance works.In addition, in any of these modes, all exist by waste gas lot of energy is discharged into situation in the atmosphere.
With waste heat discharge be now: underground heat and from the motor of other type heat of combustion gas turbine for example to other the possible waste heat source in the environment, its with a large amount of heat release in waste gas, and Reciprocating engine, it rejects heat in waste gas and the cooling water.
Just use rankine cycle system so that solve this respect of the related problem of used heat, the feasibility of its use depends on and can assemble each parts with rational economized form.Because the structure of parts must change with different applications, thereby makes that this demand is complicated.For example, because various waste heat source are in visibly different temperature, therefore utilize the single structure of the rankine cycle system of this waste heat source can not guarantee the use of the efficient and cost-effective of these waste heat source certainly.
Therefore the object of the present invention is to provide a kind of new improved closed rankine cycle electricity generating device that can use used heat effectively.
Another object of the present invention is to provide a kind of and making and using economic and effective rankine cycle turbo.
Another purpose of the present invention is more effectively to use the secondary waste heat source.
A further object of the present invention is to provide a kind of rankine cycle system of working under lower temperature and pressure.
Another object of the present invention is to provide a kind of in use economic and practical rankine cycle system.
By the reference accompanying drawing and in conjunction with following description, can understand these purposes of the present invention and other feature and advantage better.
Embodiment
Referring now to Fig. 1, wherein show typical vapor-compression cycle, it in series comprises compressor 11, condenser 12, throttle valve 13 and evaporator 14 on flow process.In this circulation, for example R-11, R-12 or R134a refrigeration agent are forced to this system that counterclockwise flows through as shown by arrows.
Be compressed to high temperature and high pressure by 11 receptions of motor 16 compressor driven from the refrigerant vapor of evaporator 14 and with it, wherein the steam of heat flows to condenser 12 subsequently, in condenser by with the cooling medium heat exchange relationship of air or water for example, steam is cooled and is condensed into liquid state.Liquid refrigerant flows to throttle valve from condenser subsequently, and wherein refrigeration agent expand into the liquid state of the two-phase of low temperature, simultaneously refrigerant flow direction evaporator 14.Liquid in the vaporizer provides cooling effect to the air or the water of the evaporator of flowing through.The steam of low pressure flows to compressor 11 subsequently, restarts circulation in compressor.
According to the size of air-conditioning system, compressor can be rotary type, screw type or the shuttle compressor that is used for mini-system, or is used for the screw compressor or the centrifugal compressor of large scale system.Typical centrifugal compressor comprises: be used to make that refrigerant vapor accelerates to impeller at a high speed; Be used to make that refrigeration agent decelerates to the diffuser that low speed converts kinetic energy to pressure energy simultaneously; And form is the discharge pumping chamber of spiral case or trap, thereby flows to condenser subsequently so that collect the steam of discharging.Drive motor 16 is electric motor normally, and it is sealed in the other end of compressor 11 airtightly, and makes that by transmission device 26 high speed shaft rotates in operation.
Typical rankine cycle system as shown in Figure 2 also comprises evaporator 17 and condenser 18, and they are to absorb respectively and release heat with above-mentioned steam compressed same way as.Yet, as described below, the direction that fluid flows in this system is compared with vapor-compression cycle and is put upside down, and compressor 11 is replaced by turbo machine 19, turbo machine be can't help motor 16 and is driven, but drive by the motive fluid in this system and its also drive generator 21 so that produce electric power.
In operation, make motive fluid evaporate as the vaporizer with a large amount of heat inputs usually, this motive fluid is water normally, but also can be refrigeration agent, and wherein steam flows to the turbo machine of dynamic supply subsequently.When leaving turbo machine, low-pressure steam flows to condenser 18, thereby wherein steam is condensed by the heat exchange relationship with cooling medium.Condensed liquid is recycled to evaporator/boiler so that finish this circulation by as shown in the figure pump 22 subsequently.
Referring now to Fig. 3, shown typical centrifugal compressor comprises electric motor 24, and it is connected so that drives impeller 27 with transmission device 26 in operation.Oil pump 28 is used for making the oil circulation through transmission device 26.When impeller 27 high speed rotating, force refrigeration agent to flow into inlet 29 through inlet guide vane 31 so as through impeller 27, diffuser 32, enter trap 33, collect the steam of discharging therein so that flow to condenser as described above.
In Fig. 4, identical device as shown in Figure 3 comes work as radial inflow formula turbo machine rather than as centrifugal compressor.Thereby motive fluid is introduced in inlet pumping chamber 34, and it was designed to as trap 33 in the past.The motive fluid nozzle 36 of radially inwardly flowing through subsequently, this structure of nozzle is identical with the structure that is used as diffuser in centrifugal compressor.Motive fluid clashes into impeller 27 subsequently, makes it rotatablely move thus.Impeller subsequently by transmission device 26 so that drive generator 24, this generator Structure is identical with the structure that is used as motor in centrifugal compressor.After the impeller 27 of flowing through, low-pressure gas is flowed through inlet guide vane 31 so that flow to exit opening 37.In this mode of operation, inlet guide vane 31 is preferably to be movable to the fully open position or to move and entirely removes from this equipment.
In aforesaid centrifugal compressor application, diffuser 32 any in can all kinds is comprising vaned diffuser or vaneless diffuser.A kind of vaned diffuser of known type is the known pipe diffuser that discloses in U. S. Patent 5145317, and this patent transfers assignee of the present invention.By reference character 38 expressions, it is circumferentially around impeller 27 in Fig. 5 for this diffuser.At this, backswept impeller 27 is along turning clockwise as shown in the figure, and high-pressure refrigerant is radially outwardly along the arrow diffuser 38 of flowing through.This diffuser 38 has a plurality of circumferential isolated tapered portion or wedge-like portion 39, and tapered channels 41 is formed on therebetween.The compressed refrigeration agent tapered channels 41 as shown in the figure of flowing through radially outwardly subsequently.
In the application of centrifugal compressor as shown in Figure 6 turbine rotor, impeller 27 is along as shown in the figure counter clockwise directions rotation, and wherein impeller 27 is driven by motive fluid, and this motive fluid is as shown in figure along the arrow radial tapered channels 41 of inwardly flowing through.
Therefore, the structure identical be used as diffuser 38 in centrifugal compressor can be used as the collection part of nozzle or nozzle in purposes of turbine application.In addition, this nozzle arrangements provides the advantage of the nozzle arrangements that is better than prior art, for special operating conditions, can improve its performance, and this will be in following detailed description.For difference and the advantage of describing the nozzle arrangements that is higher than prior art, referring now to Fig. 7 A and 7B.
With reference to Fig. 7 A, the nozzle arrangements of shown prior art is described with reference to the impeller 42 that is provided with placed in the middle, and this impeller receives the motive fluid from the nozzle member 43 of a plurality of circumferential settings.The radial extension of this nozzle 43 is limited by internal diameter R1 and external diameter R2 as shown in figure.As can be seen, independent nozzle member 43 is shorter, dwindles section area from external diameter R2 at once to internal diameter R1.In addition, nozzle member is obviously crooked on its compression-side 44 and suction side 46, causes thus as shown in the figure along the flow through obvious turning of gas of nozzle member of arrow.
The advantage of above structure of nozzle is that the equipment integral size is less.For this reason, Jue Daduoshuo (nearly all) nozzle arrangements that is used for purposes of turbine application belongs to this structure.Yet in this structure, have some shortcomings.For example, the nonuniformity of nozzle turning loss and exit flow causes nozzle efficiency to descend.These losses are considered to less, and it has been generally acknowledged that the advantage for the equipment that obtains reduced size, and these losses are worth.Certainly should be appreciated that such nozzle can not be with respect to flow direction inversely as diffuser, this is that therefore flowing separation to occur because the high rate that turns to is slowed down with quick.
With reference to Fig. 7 B, shown in nozzle arrangements of the present invention in, impeller 42 is circumferentially centered on by a plurality of nozzle members 47.As can be seen, nozzle member is length, narrow and straight substantially.Compression-side 48 and suction side 49 are linear, and relatively long and slow flaring passage 51 is provided thus.In the border of flaring passage 51, compression-side 48 and suction side 49 folded angles are cone angle alphas, and it is preferably less than 9 degree, and as can be seen, the center line of these circular cones that are illustrated by the broken lines in the drawings is straight.Because nozzle member 47 is long, the ratio of R2/R1 greater than 1.25 and preferred range be 1.4.
Because the ratio of R2/R1 is bigger, so the overall dimension of equipment has the increase (being that scope is 15%) of appropriateness with respect to the conventional nozzle structure shown in Fig. 7 A.In addition, because passage 51 is longer, so frictional loss is greater than the frictional loss of the conventional nozzle shown in Fig. 7 A.Yet this nozzle arrangements has the advantage on the performance.For example, owing to do not have turning loss or do not have the nonuniformity of exit flow, so nozzle efficiency explains with respect to the conventional nozzle structure to show and increases, even also be like this under the situation of considering above-mentioned frictional loss.The scope of the raising of this efficient is 2%.In addition, because this structure is based on diffuser design, so it can be used for turbo machine and these two kinds of application of compressor as described above, below will be described in more detail.
If being used for organic rankine cycle turbine application is identical with the equipment that is used for centrifugal compressor application, then the application's claimant recognizes and must use different refrigeration agents.That is to say that if the refrigeration agent R-134a of known centrifugal compressor is used for the application of organic rankine cycle turbo, then pressure is with excessive.Promptly, in using the centrifugal compressor of R-134a as refrigeration agent, pressure range between 50-180psi, and if identical refrigeration agent be used for purposes of turbine application of the present invention, then pressure will be elevated to about 500psi, and this is greater than the maximum design pressure of compressor.Therefore, for the claimant, must obtain the another kind of refrigeration agent that can be used for turbine application.Therefore, the claimant has found refrigeration agent R-245fa, and when this refrigerant applications during in turbine application, it is worked in the pressure range of 40-180psi, chart as shown in Figure 8.This pressure range is acceptable for the hardware that is designed for centrifugal compressor applications.In addition, for the temperature range of this turbine system that uses R-245f a in 100-200 scope, this is acceptable for the hardware that is designed for centrifugal compressor applications, and operating temperature is in 40-110 scope in centrifugal compressor.Therefore in Fig. 8 as can be seen, the air-conditioning system that is designed for R-134a can be used for the power generation application of organic rankine cycle under the situation of using R-245fa.In addition, have been found that identical equipment can use (for example 270 ° shown in the dotted line among Fig. 8 and 300psia) safely and effectively in higher temperature and the pressure range because existing compressor has extra margin of safety.
Under the situation of describing turbo machine of the present invention part, below will consider the related system parts that will use with turbo machine.With reference to Fig. 9, aforesaid turbo machine is represented by reference character 52 that in the drawings it can obtain as Carrier 19XR2 centrifugal compressor as ORC (organic rankine cycle) turbine/generator on market, and it can reverse as described above work.The ebullator of this system or evaporator section are represented by reference character 53 that in the drawings it is used for the high temperature R-245fa refrigerant vapor of elevated pressures is supplied to turbine/generator 52.According to one embodiment of the present of invention, can realize that its trade name is 16JB by the steam generator of the Carrier Limited Korea that on market, obtains for the needs of this boiler.
The energy that is used for boiler 53 is represented by reference character 54 in the drawings, and can is any type of used heat that is discharged into usually in the atmosphere.For example, for the small gas turbo machine for example Capstone C60 be commonly referred to for the Microturbine, heat can obtain from the waste gas of Microturbine.It can also be Pratt﹠amp for example; Whitney FT8 is the large-scale combustion gas turbine of combustion gas turbine fixedly.Another kind of practical used heat is from internal-combustion engine large reciprocating diesel engine for example, thereby it is used for driving high-rating generator and produces a large amount of heats by combustion gas and by liquid coolant in the circulation of radiator and/or lubrication system at work.In addition, energy can obtain from the heat exchanger that is used for the turbosupercharger interstage cooler, and wherein the compressed combustion air of Liu Ruing is cooled so that realize higher efficient and the performance of Geng Gao.
At last, the heat energy that is used for ebullator can obtain from underground heat or garbage loading embeading flaring waste gas.In these cases, combustion gas can directly apply to ebullator so that produce refrigerant vapor, or by at first utilizing these source gas-powered motors, thereby the heat that makes motor emit again can be utilized is as described above used indirectly.
Through after the turbo machine 52, so that make vapour condensation get back to liquid, this liquid is pumped into boiler 53 by pump 57 subsequently through condenser 56 for it at refrigerant vapor.Condenser 56 can be any in the known type.Discovery is applicable to that one type of this application is to be the air cooled condenser of 09DK094 from the obtainable model of Carrier Corporation on market.Suitable pump 57 is the Sundyne P2CZS that obtain on market.
Consider that aforesaid equipment can use most effectively so that utilize the degree of obtainable energy from used heat, the temperature range that is appreciated that the most common waste heat source is very different.For example, the temperature most probable of flaring is in 1100 scope, yet the temperature of circuit fluid is 300 °F in Reciprocating engine, and the exhaust gas temperature of Reciprocating engine is 700 °F.In combustion gas turbine, exhaust gas temperature changes in 400-750 scope according to structure.If in these applications each, use identical rankine cycle system, then its effect is a deterioration of efficiency.Therefore, desirable is to change its design so that adapt to special application.
Referring now to following table 1, it has listed the various application that are used for centrifugal compressor and are used for organic rankine cycle turbo.These are used according to the recently best statement of pressure, wherein for compressor application, and pressure ratio P
REqual P
Condenser/ P
Evaporator, for purposes of turbine application, pressure ratio P
REqual P
Evsporaror/ P
CondenserTherefore, the claimant for example has been found that for the centrifugal compressor of working under the benign environment condition, and pressure ratio 2: 1st is desirable.If use identical equipment in organic rankine cycle turbo in the application of low difference journey, then pressure ratio should be 4: 1, and as T for example under cryogenic conditions relatively
Gas<300 or T
Steam<225 °F when using, this is the most effective and the most efficiently.In in these applications each, rotor or impeller have the BI blade as shown in figure 10.Therefore, the single compressor/turbine that has this backswept impeller can be exchanged in these two application effectively, effectively and efficiently heats its demand thus.
Table 1
Compressor |
Turbo machine |
P
R=2: 1 mild temperature (T
Cond, sat-T
Evap, sat)=55
|
P
R=4: 1.Low-grade waste heat (T
Gas<300 or T
Steam<225 °F, cause refrigeration agent boiling temperature Trefr, seethe with excitement<200 °F)
|
P
R=3: 1 tropical climate (T
Cond, sat-T
Evap, sat)=70
|
P
R=6: 1.(300<T of middle grade used heat
Gas,<500 or 225<T
Steam/water<300 °F, cause 200<refrigeration agent boiling temperature Trefr, seethe with excitement<275 °F)
|
P
R=4.5: 1 ice-reserving/discrepancy in elevation journey (T
Cond, sat-T
Evap, sat)=80
|
P
R=10: 1.High grade waste heat (T
Gas>500 or T
Steam>300 °F, cause refrigeration agent boiling temperature Trefr, seethe with excitement>250 °F)
|
Usually, the used heat of the middle grade of application of the tropical climate of centrifugal compressor refrigerator and/or turbo machine is used, and the impeller that the claimant finds to have the blade of radially aiming at as shown in figure 11 is the most effective and most economical in these are used.
At last, for being used for the ice-reserving/centrifugal compressor of discrepancy in elevation journey and the purposes of turbine application of high grade waste heat, the FC turbo machine is preferred as shown in figure 12, and wherein the pressure ratio of compressor is that 4.5: 1 and turbine pressure ratio are 10: 1.
Other factor can change above-mentioned application.For example, if heat release (condenser) is water-cooled rather than air-cooled, can increase for the obtainable poor journey/pressure ratio of turbo machine, (water-cooled makes and acquires lower condensation saturation temperature, therefore can obtain lower condensation saturation pressure, increase the pressure ratio of boiling pressure/condensing pressure thus).Therefore, middle grade used heat may need the FC impeller.